Reentrant circuits do not require two separate pathways with different refractory periods or conduction velocities. true or false?

Reentrant circuits do not require two separate pathways with different refractory periods or conduction velocities. true or false?

• A. True
• B. False
• C. Depends on tissue
• D. Cannot occur

Answer: (B)

False. Reentrant circuits rely on differing properties along the circuit—such as one path recovering excitability earlier or conducting more slowly than another—so a premature impulse can block in one direction but propagate in the other. This creates a unidirectional block and allows the wavefront to circle back and re-enter tissue that has just recovered, sustaining the loop. If both pathways had identical conduction and refractoriness, the impulse would not create a reliable unidirectional block, and sustained reentry would be unlikely. Differences in conduction velocity or refractoriness are therefore essential for reentry to occur.

False. Reentrant circuits rely on differing properties along the circuit—such as one path recovering excitability earlier or conducting more slowly than another—so a premature impulse can block in one direction but propagate in the other. This creates a unidirectional block and allows the wavefront to circle back and re-enter tissue that has just recovered, sustaining the loop. If both pathways had identical conduction and refractoriness, the impulse would not create a reliable unidirectional block, and sustained reentry would be unlikely. Differences in conduction velocity or refractoriness are therefore essential for reentry to occur.